Conventional griddle plates or platens are made from steel or cast iron and are heated by tubular sheathed elements as, for example, disclosed in U.S. Pat. No. 3,843,315. The heating elements are maintained in contact with the underside of the griddle plate by a clamping system to maximize heat transfer and prevent overheating of the heating elements. The clamping system involves a substantial and often complex metal fabrication that adds cost and weight to the cooking appliance. The clamping system is secured to the griddle plate by a large number of studs that are screwed into holes or welded on to the griddle plate. This also adds cost and weight to the cooking appliance.
A non-contact grill is described in U.S. Pat. No. 6,614,007 as having one or more separate heater boxes secured to the underside of the griddle plate. Separate infrared heating elements are disposed in the heating boxes so as to be separated by a gap from the underside of the griddle plate. This arrangement provides a substantially uniform heating to the underside of the griddle plate.
It is desirable to have a grill that attains a substantially uniform temperature during pre-heat and recovery modes. It is also desirable to have a grill with separate heating zones that can be independently operated such that the heat of an operating zone does not significantly affect the heating of an adjacent zone.
Thus, there is a need for a grill that attains a substantially uniform temperature throughout its platen during pre-heat and recovery modes.
There is also a need for a grill with heating zones that have minimal heat migration to adjacent zones.